Although damage was considered light, several loss estimates equaled or exceeded $2 million, and six injuries resulted when two vehicles came down with the partial collapse of a highway overpass on US 101 in Fields Landing.

Several types of sensors were installed at the site to capture strong motion data in this seismically active area, but the majority of records from the event were considered unreliable due to faulty equipment or inadequate maintenance.

[6] The earthquake occurred offshore (to the northwest of Eureka, about 37 mi (60 km) west of Patrick's Point) and had a maximum Mercalli intensity of VII (Very strong).

In Fields Landing, King Salmon, Loleta, and Big Lagoon areas, the strongest effects included surface cracks on the ground, soil liquefaction, small landslides and rockfalls, and numerous slumps along the Eel River.

At the time of the shock, two of the southbound spans came off their support (a 6 in (15 cm) ledge) and six people were injured when a Volkswagen Beetle and a small pickup truck plummeted off the bridge.

The Nuclear Regulatory Commission performed a post-event survey of the facility's systems in late 1980, but inspectors found only minor effects to the plant's structure, piping, tanks, and other mechanical equipment.

It was found that the two units were automatically shut down at the time of the shock for various protective concerns and that there were minor cracks in masonry and concrete, sheared bolts, pipe leaks, and slight movement of water tanks.

[9] Pacific Gas and Electric initially reported that peak ground accelerations in the range of 0.16–0.4 g were recorded on the floor of the refueling building on the plant's strong motion instruments (accelerometers).